Tissue annuloplasty band and apparatus and method for fashioning, sizing and implanting the same

ABSTRACT

This invention relates to a system used to fashion, size, and implant a tissue annuloplasty band. This system comprises (1) a device to cut tissue; (2) a device to fashion (i.e., roll, fold, bunch, etc.) the tissue into a band (i.e., the tissue annuloplasty band); and (3) a sizer that comprises an mounting ring which allows for determining and maintaining the proper size and shape of the tissue annuloplasty band while it is attached to the annulus of a heart valve. These components can be used alone, together as a system, or in any combination to fashion, size, and/or implant the tissue annuloplasty band.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/760,222, filed Jan. 12, 2001 and now U.S. Pat. No. 6,942,694, by JohnR. Liddicoat et al. for TISSUE ANNULOPLASTY BAND AND APPARATUS ANDMETHOD FOR FASHIONING, SIZING AND IMPLANTING THE SAME, which in turnclaims the benefit of U.S. Provisional Patent Application No.60/176,046, filed Jan. 14, 2000 by John R. Liddicoat et al. forINSTRUMENTS AND METHODS TO FASHION, SIZE, AND IMPLANT A TISSUEANNULOPLASTY DEVICE.

The above-identified patent applications are hereby incorporated hereinby reference.

FIELD OF THE INVENTION

The present invention relates to the correction of valvular heartdisease. In particular, it relates to the fashioning, sizing andimplanting of tissue as an annuloplasty band or ring to be used for thecorrection of valvular heart disease.

BACKGROUND OF THE INVENTION

The human heart comprises four heart valves. Two of these valves arelocated between the left and right atria and ventricles and are calledthe mitral and tricuspid valves, respectively. These valves serve tomaintain one-way blood flow into the ventricles and to prevent theregurgitation of blood back into the atria. Although the presentinvention can be used for many different applications including mitraland tricuspid valve repair, for the purposes of example it willhereinafter be described in connection with the repair of a mitralvalve.

Mitral valve repair is the surgical procedure of choice to correctmitral regurgitation of all etiologies. With the use of current surgicaltechniques, approximately 70 to 95% of all regurgitant mitral valves canbe repaired. The advantages of mitral valve repair over mitral valvereplacement are well documented. These advantages include betterpreservation of cardiac function and reduced risk ofanticoagulant-related hemorrhage, thromboembolism and endocarditis.

Nearly all mitral valve repairs include an annuloplasty. Theannuloplasty consists of implanting a prosthetic band or ring thatsurrounds all or part of the circumference of the annulus of the valve.The annuloplasty serves several functions: it remodels the annulus,decreases tension on suture lines, increases leaflet coaptation, andprevents recurrent annular dilation. In addition, the annuloplastyimproves repair durability.

The placement of a prosthetic annuloplasty band or ring in the heartresults in a risk of thromboembolism and infection; these risks areunavoidable and persist for the life of the patient. Formation of bloodclots on prosthetic materials in the heart often results in stroke, andinfection of a prosthetic annuloplasty band or ring may lead tolife-threatening sepsis and the need for urgent re-operation.

The ideal annuloplasty would be effected using a universally flexible,autologous material. Such a material does in fact exist, in the form ofthe patient's own pericardium. The pericardium is the sac in which theheart sits. The pericardium is often used by heart surgeons to repaircongenital heart defects. It heals well, and almost never becomesinfected. However, the pericardium can be difficult to work with.

In order to make practical use of autologous pericardium for a mitralvalve annuloplasty, the surgeon would need apparatus to facilitate thecreation of a tissue annuloplasty band or ring of the appropriate lengthand thickness, and to ensure that the tissue annuloplasty band or ringwill maintain the chosen dimensions while it is applied to the heart.

The development of a system for constructing and deploying a pericardialannuloplasty band or ring would have great benefit for the patient. Noprosthetic material would be placed in the heart, greatly reducing therisk of thromboembolism and infection. No anticoagulation would benecessary. In addition, pericardium remains flexible as it heals, andthis would result in preserved mitral valve physiology.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide apericardial annuloplasty band.

Another object of the present invention is to provide apparatus andmethods that facilitate the construction of a precisely measuredannuloplasty band from the patient's own pericardium.

Still another object of the present invention is to provide a templateupon which the fashioned tissue annuloplasty band is mounted,facilitating sizing and placement of the tissue annuloplasty band in theheart and ensuring that the tissue annuloplasty band maintains its shapeduring application.

These and other objects are addressed by the present invention whichcomprises a tissue annuloplasty band and apparatus and methods forfashioning, sizing and implanting the same. In one preferred form of thepresent invention, the graft tissue is first cut to an appropriate size.Then the cut tissue is fashioned into the appropriate shape, i.e., anelongated length. If desired, an internal or external support structuremay be provided to help support and/or manipulate the elongated lengthof tissue. Next, the elongated length of tissue is mounted onto anadjustable mounting ring so as to form a tissue annuloplasty band. Thenthe appropriate size and shape of the tissue annuloplasty band isdetermined. This is done by directly measuring the mitral valve, or byplacing the tissue annuloplasty band (which is mounted on the adjustablemounting ring) in the left atrium and visually comparing it against thepatient's mitral valve. The size of the tissue annuloplasty band is thenadjusted, by adjusting the size of the adjustable mounting ring, untilthe tissue annuloplasty band is the appropriate size. Any excess tissueis marked for later excision. Next, sutures are placed through thepatient's annulus and through the tissue annuloplasty band, which isstill seated on the adjustable mounting ring. The tissue annuloplastyband is then guided into place with the assistance of the adjustablemounting ring. Then the tissue annuloplasty band is tied down intoplace, while the tissue annuloplasty band is still mounted onto theadjustable mounting ring, so as to maintain its shape and length duringfinal seating. Once the tissue annuloplasty band has been tied intoplace, the tissue annuloplasty band is dismounted from the adjustablemounting ring. The adjustable mounting ring is then removed, and anyexcess tissue previously marked is excised.

In another preferred form of the invention, the adjustable mounting ringmay be replaced by a set of pre-sized mounting rings. In this case, anappropriate one of the pre-sized mounting rings is selected by directlymeasuring the mitral valve or by placing different pre-sized mountingrings in the left atrium and visually comparing them against thepatient's mitral valve. Once the appropriate pre-sized mounting ring hasbeen selected, the elongated length of graft tissue is mounted onto thepre-sized mounting ring and then the remainder of the annuloplasty isperformed in the manner described above.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will befurther disclosed in the following detailed description of the preferredembodiments of the invention, which is to be considered together withthe accompanying drawings wherein like numbers refer to like parts andfurther wherein:

FIG. 1 is a schematic view of a male/female cutting die used in onepreferred form of the invention;

FIG. 2 is a schematic view showing graft tissue being rolled into thetissue annuloplasty band while on the male cutting die;

FIG. 3 is a schematic view showing a first sizer formed in accordancewith the present invention, with the first sizer's handle extendingperpendicular to the plane of the sizer's adjustable mounting ring;

FIG. 4 is a view like that of FIG. 3, except showing the rear side ofthe first sizer shown in FIG. 3;

FIG. 5 is a schematic view of the distal end of the first sizer, withthe adjustable mounting ring being shown in its largest diameterconfiguration;

FIG. 6 is a schematic view of the distal end of the first sizer, withthe adjustable mounting ring being shown in its smallest diameterconfiguration;

FIG. 7 is a schematic end view of the distal end of the first sizer,with the adjustable mounting ring being shown in its smallest diameterconfiguration;

FIG. 8 is a schematic view showing a second sizer formed in accordancewith the present invention, with the second sizer's handle extendingparallel to the plane of the sizer's adjustable mounting ring;

FIG. 9 is a schematic view of the distal end of the second sizer, withthe adjustable mounting ring being shown in its largest diameterconfiguration;

FIG. 10 is a schematic side view of the distal end of the second sizer,with the adjustable mounting ring being shown in its largest diameterconfiguration;

FIG. 11 is a schematic view of the distal end of the second sizer, withthe adjustable mounting ring being shown in its smallest diameterconfiguration;

FIG. 12 is a schematic view showing the tissue annuloplasty ring mountedon the second sizer's adjustable mounting ring;

FIG. 13 is a schematic view showing a set of third sizers, wherein eachof the third sizers comprises a pre-sized mounting ring;

FIG. 14 is a schematic view showing manual sizing of the graft tissueused for the tissue annuloplasty band;

FIG. 15 is a schematic view of a guide tube used to help guide the grafttissue through an external mesh;

FIG. 16 is a schematic view showing the external mesh, guide tube andtissue hook;

FIG. 17 is a schematic view showing the graft tissue prior to beingdrawn into the guide tube;

FIG. 18 is a schematic view showing the graft tissue after it has beendrawn into the guide tube;

FIG. 19 is a schematic view showing the guide tube being removed and thetissue being cut to fit the external mesh;

FIG. 20 is a schematic view showing the tissue secured within theexternal mesh and after synching the end purse-string sutures closed,forming the tissue annuloplasty band;

FIG. 21 is a schematic view showing the tissue annuloplasty band beingattached to a pre-sized (i.e., fixed-diameter) mounting ring; and

FIG. 22 is a schematic view showing the tissue annuloplasty bandattached to a pre-sized, fixed-diameter mounting ring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention relates to the rapid fashioning, sizing, and implantingof a tissue annuloplasty band for the general purpose of cardiac valverepair. Although the description provided herein describes the use ofthe system for mitral valve repair, the apparatus and method may be usedfor other applications as well. Therefore, the following description isintended merely as an example of how the apparatus and method of thepresent invention may be used, and not by way of limitation.

In accordance with the present invention, the graft tissue (i.e.,pericardium, vein, or other autologous or non-autologous tissue) isfirst cut to an appropriate size. This may be done with any appropriatecutting tool. Preferably, however, a male/female cutting die is used tocut the tissue into the general size and shape appropriate to create thetissue annuloplasty band.

More particularly, and looking now at FIG. 1, there is shown amale/female cutting die 10. Cutting die 10 comprises a male die 20having a groove 30 formed therein, and a female die 40 having a window50 formed therein. When a piece of donor tissue (e.g., pericardium) isplaced between male die 20 and female die 40, and the two die membersare thereafter brought together, a piece of graft tissue (correspondingin size to window 50 in female die 40) will be cut from the donortissue.

Once the graft tissue has been cut to an appropriate size, it is thenfashioned into the appropriate shape, i.e., an elongated length. Thismay be done by rolling, folding, bunching, etc.

In one preferred form of the invention, the tissue is rolled about anaxle using the male die as the base. More particularly, and looking nowat FIG. 2, after a piece of graft tissue 60 has been cut, and whilegraft tissue 60 is lying on male die 20, an axle 70 is pressed down intogroove 30. Then one tissue end 80 is folded over the other tissue end90, and axle 70 is rolled, so as to form a tissue annuloplasty band 100.If desired, an adhesive, a sealant, a medication or the like may beapplied to the tissue. By way of example, an adhesive might be appliedto a final rolled edge so as to keep the tissue annuloplasty band fromunrolling. Axle 70 is made of a relatively flexible material such aspliable plastic or metal. The body of the axle, while being flexible,may or may not stretch along its linear axis. The two ends 110A, 110B ofaxle 70 preferably have elastic properties, allowing these portions ofthe axle to stretch along their linear axis.

Once the graft tissue has been rolled into tissue annuloplasty band 100,it is mounted onto a mounting ring for sizing and implanting. This maybe implemented in a variety of ways, using a variety of devices.

In one preferred form of the invention, and looking now at FIGS. 3-7, afirst sizer 120 is used. First sizer 120 comprises a handle 130 and anadjustable mounting ring 140. Handle 130 preferably comprises twocylinders 150, 160 which are able to move relative to one another.Cylinder 150 is connected to mounting ring 140 by a drive cable 170(shown in phantom). Drive cable 170 is in turn connected to a centralbevel gear 180 (FIG. 7) in adjustable mounting ring 140. Rotation ofcentral bevel gear 180 in turn causes the additional bevel gears 190 torotate. These bevel gears 190 are coupled to threaded shafts 200.Adjustable mounting ring segments 210 are internally threaded and rideon the threaded shafts 200. The rotation of threaded shafts 200 causesmounting ring segments 210 to move radially and hence causes adjustablemounting ring 140 to expand and contract (i.e., to change in radialdimension). Accordingly, it will be seen that rotation of cylinder 150relative to cylinder 160 results in a change in the geometry (i.e., thesize) of adjustable mounting ring 140. Cylinder 160 (i.e., the one thatis not connected to adjustable mounting ring 140 by drive cable 170)serves as the support portion of the handle and remains in a relativelyfixed orientation with respect to adjustable mounting ring 140. Cylinder160 may have a constant outer diameter or, alternatively, it may have astepped outer diameter such as that shown in FIGS. 3 and 4. Handle 130also has a size indicator 220 on the outside of cylinder 160 that showsthe size of the tissue annuloplasty band after it has been properlysized.

As mentioned above, adjustable mounting ring 140 is (i) connected tocylinder 150 by drive cable 170, and (ii) fixed to cylinder 160.Adjustable mounting ring 140 comprises a central body 230 that containsthe aforementioned bevel gears 180 and 190. These gears 180 and 190 arein turn coupled to the mounting ring segments 210 to which the tissueannuloplasty band 100 will be attached. These mounting ring segments 210are attached to central body 230 by the threaded shafts 200.Accordingly, movement of the aforementioned bevel gear 180 via cable 170causes the mounting ring segments 210 to expand and contract relative tocentral body 230. Hence, the tissue annuloplasty band 100 can beadjusted to the appropriate size for varying patient anatomies. Mountingring segments 210 can have additional support, e.g., by lateral stays240 interacting with each other. The outer edge 250 of each segment 210preferably has a groove 260 in which the tissue annuloplasty band 100 ismounted.

With the aforementioned first sizer 120, the sizer's handle 130 extendsperpendicular to the plane of the sizer's adjustable mounting ring 140.Alternatively, and looking now at FIGS. 8-11, there is shown a secondsizer 120A in which the sizer's handle 130 extends parallel to the planeof the sizer's adjustable mounting ring 140.

The tissue annuloplasty band 100 (FIG. 2) is placed into groove 260 onadjustable mounting ring 140 (FIG. 12). Then the elastic ends 110A, 110Bof axle 70 are attached to one another. This creates tension on thetissue, which keeps the tissue annuloplasty band 100 in the groove 260on the mounting ring. Clamps, ties or sutures can be applied asnecessary for increased stability.

Next, the appropriate size and shape of the tissue annuloplasty band 100is determined. To do this, the tissue annuloplasty band 100, which isnow mounted on adjustable mounting ring 140, is placed in the patient'sleft atrium and visually compared to the patient's mitral valve.Alternatively, the mitral valve may be measured directly. The surgeonthen adjusts the size of tissue annuloplasty band 100 by turningcylinder 150 of handle 130 until tissue annuloplasty band 100 isappropriately sized. Any excess tissue is marked for later excision.

Next, sutures are placed through the patient's annulus and subsequentlythrough the tissue annuloplasty band 100. The tissue annuloplasty band100 is then guided into place with the assistance of sizer 120 (or120A). Tissue annuloplasty band 100 is then tied down into place, whileit is still mounted on adjustable mounting ring 140, so as to maintainits shape during final seating. Once tissue annuloplasty band 100 hasbeen tied into place, the elastic ends 110A, 110B of axle 70 aredetached from one another. Any other stabilizing components such asclamps, ties, or sutures that aided in mounting tissue annuloplasty band100 to adjustable mounting ring 140 are detached. Adjustable mountingring 140 is then removed, and axle 70 is withdrawn. Any excess tissuepreviously marked is excised.

If desired, sizer 120 (120A) can be constructed so that handle 130 maybe detached from adjustable mounting ring 140. With such a construction,handle 130 may be removed after guiding tissue annuloplasty band 100 tothe surgical site, but before the band is removed from adjustablemounting ring 140.

It is also possible to practice the present invention using a pre-sized,fixed diameter mounting ring. More particularly, and looking now at FIG.13, there is shown a set of third sizers 120B, wherein each of the thirdsizers 120B comprises a pre-sized, fixed diameter mounting ring 140B(preferably having a peripheral groove 260B) and an associated handle130B. Each mounting ring 140B may comprise a complete circle (e.g., asshown in FIG. 13) or only a portion of a circle (e.g., as shown in FIG.22). In this form of the invention, an appropriate one of the pre-sizedmounting rings 140B is selected by directly measuring the mitral valveor by placing different pre-sized mounting rings in the left atrium andvisually comparing them against the patient's mitral valve. Once theappropriate pre-sized mounting ring 140B has been selected, tissueannuloplasty band 100 (FIG. 2) is mounted onto the pre-sized mountingring 140B, i.e., by slipping tissue annuloplasty band 100 into theperipheral groove 260B and attaching elastic ends 110A, 110B of axle 70together. Then tissue annuloplasty band 100 is transferred to theannulus of the patient's mitral valve in the manner previouslydescribed.

In another preferred form of the invention, and looking at FIGS. 14-22,a tissue annuloplasty band 100A (FIG. 20) is formed using an externalstructural mesh 300 (FIG. 16). More particularly, graft tissue 310 (FIG.14) is cut into a preferred long length 320 using a tissue grasper 330and a tissue cutter 340, both being standard, commercially-availabledevices. To aid in inserting tissue length 320 into external mesh 300, atemporary guide tube 342 (FIG. 15) may be used to hold open the externalmesh 300 and guide the tissue length 320 through the mesh.

Looking at FIG. 16, external mesh 300 is preferably constructed offlexible but not stretchable material such as monofilament or braidedsuture for permanent implantation into the body. The weave is preferablyconstructed such that mesh 300 does not stretch in the direction of thelong axis via straight members 350. The weave could also provide a largemesh 360 to allow a significant amount of tissue to be exposed to theimplant surface so as to promote implant-to-body tissue in-growth. Pursestring sutures 370 at the end of mesh 300 provide a means to secure thetissue graft 320 inside the external mesh and to secure the resultingtissue annuloplasty band 100A to the mounting ring 140 (or 140B). Ifvarious lengths of bands are required, either individual bands could beprovided or a longer band could be cut to the required length. If alonger band is cut to length, extra sets of purse string sutures 370Aprovide a means to shorten the band and still secure the tissue 320within the external mesh. Any unused purse string sutures 370, 370A canbe cut prior to fixation of the band to the mounting ring.

Looking at FIG. 16, guide tube 342 has been inserted through externalmesh 300 to provide a smooth path for tissue 320. A tissue hook 382 andshaft 384 are inserted through guide tube 342, and then tissue 320 isfolded in half and inserted through hook 382 (FIG. 17). For thisembodiment, tissue 320 must be at least twice as long as the pre-sizedband length. An alternative to hook 382 is a grasper (not shown) thatpulls a single length of tissue through guide tube 342. For such analternative embodiment, a single length of tissue might be wider than afolded length of tissue, such that the volume of tissue inside theexternal mesh 300 is similar in both embodiments.

Looking next at FIGS. 18-20, the tissue 320 is pulled through guide tube400 by pulling on tissue retraction handle 386. Guide tube 342 is thenpulled out from between tissue 320 and external mesh 300. Any excesstissue 320 is cut to the length of external mesh 300 and purse stringsutures 370 are tied closed at 387 to secure the tissue 320 withinexternal mesh 300, forming a properly sized tissue annuloplasty band100A.

Looking at FIGS. 21 and 22, tissue annuloplasty band 100A is temporarilysecured to a mounting ring (e.g., a pre-sized fixed-diameter mountingring 140B) by tying a knot 388 (FIG. 22) using the remaining lengths ofpurse string sutures 370. Once the surgeon has sutured the tissueannuloplasty band 100A to the mitral valve using standard surgicaltechniques, mounting ring 140B is removed by cutting and retrievingpurse string sutures 370 close to the ends of tissue annuloplasty band100A.

It is to be understood that the present invention is by no means limitedto the particular constructions and method steps disclosed above and/orshown in the drawings, but also comprises any modifications orequivalents within the scope of the claims.

1. A method for performing an annuloplasty on a heart valve, the methodcomprising the steps of: providing an elongated length of autologous ornon-autologous graft tissue; fashioning the elongated length of grafttissue into an elongate band comprising a plurality of overlaid layersof the graft tissue; wherein the fashioning comprises rolling theelongated length of graft tissue along an axis thereof so as to createthe band comprising the plurality of overlaid layers of graft tissue;sizing the elongate band to the annulus of the valve; and implanting theelongate band of graft tissue onto the annulus of the valve; wherein theelongated length of graft tissue is rolled about a flexible axle havingtwo opposing ends, and further wherein the step of implanting theelongate band of graft tissue comprises the following sub-steps: (a)positioning the band around the annular peripheral surface of a mountingring, (b) attaching the opposing ends to one another so as to secure theband to the mounting ring, (c) using the mounting ring to position theelongate band of graft tissue proximate the annulus of the valve, (d)securing the elongate band of graft tissue onto the annulus of thevalve, and (e) separating the mounting ring from the elongate band ofgraft tissue.
 2. A method according to claim 1 wherein the step ofsizing comprises the sub-steps of: providing a set of pre-sized, fixeddiameter mounting rings; selecting, from the set of pre-sized, fixeddiameter mounting rings, a particular mounting ring having a sizecorresponding to the size of the annulus of the valve; and positioningthe elongate band of graft tissue onto the selected mounting ring;wherein the implanting of the elongate band of graft tissue comprisesusing the mounting ring to position the elongate band of graft tissueproximate to the annulus.
 3. A method according to claim 1 wherein thetissue comprises pericardium.
 4. A method according to claim 1 whereinthe tissue is autologous.
 5. A method according to claim 1 wherein thetissue is non-autologous.
 6. A method for performing an annuloplasty ona heart valve, the method comprising the steps of: fashioning anelongated length of autologous or non-autologous graft tissue into anelongate substantially solid band comprising a plurality of overlaidlayers of the graft tissue; sizing the elongate substantially solid bandof autologous or non-autologous graft tissue to the annulus of thevalve; and implanting the sized elongate substantially solid band ofautologous or non-autologous graft tissue onto the annulus of the valvewherein the band of tissue is sized by positioning thereof on anadjustable mounting ring and adjusting the size of the adjustablemounting ring, and further wherein the mounting ring is used to guidethe band of tissue into place for implantation.
 7. A method according toclaim 6 wherein the mounting ring comprises a plurality of segments thatare movable radially and bidirectionally relative to a center axis.
 8. Amethod according to claim 6 wherein the band of tissue is autologous. 9.A method according to claim 6 wherein the band of tissue comprisespericardium.
 10. A method according to claim 6 wherein the implanting ofthe band of tissue comprises mounting the band of tissue onto theannular peripheral surface of the mounting ring, using the mounting ringto position the band of tissue proximate the annulus of the valve,attaching the band of tissue to the annulus of the valve, and thereafterdetaching the ring from the band of tissue.
 11. A method according toclaim 10 wherein the band of tissue is mounted to the mounting ring byan elongate flexible member that extends within and lengthwise of theband of tissue and has opposite ends that are tied to one another, andfurther wherein the elongate flexible member is withdrawn from the bandof tissue after the band of tissue has been attached to the annulus ofthe valve.